A can of tuna is one of the easiest high-protein foods to estimate once you know two things: the can size and whether the nutrition label lists drained or undrained weight. In most standard cans, you’ll get roughly 25 to 30 grams of protein per can, but the exact amount can vary.
This guide shows you how to calculate the protein in your tuna in a few simple steps, compare tuna types, and avoid the most common tracking mistakes.
1) Check the can size and serving basis
Start by looking at the net weight on the can and, more importantly, the serving size on the Nutrition Facts label. Tuna is often listed by serving, not by the whole can, so a single can may contain more than one serving.
A standard 5-ounce can of tuna often ends up around 25 to 30 grams of protein once drained, but smaller snack cans and larger family-size cans can be very different. If you only remember one thing, remember that the label is the most reliable starting point.
2) Read the label for protein per serving
Find the protein grams per serving on the Nutrition Facts panel, then multiply by the number of servings in the can. For example, if one serving has 13 grams of protein and the can has two servings, the full can provides about 26 grams of protein.
If the label lists the tuna as ‘drained solids,’ use the drained amount. If it lists the tuna in oil or water without drained values, draining can change the total weight but not the protein in the fish itself.
3) Adjust for tuna type and packing liquid
Light tuna, albacore tuna, chunk-style tuna, and solid tuna can all have slightly different nutrition values. The differences are usually modest for protein, but they can matter if you track calories or fat too.
Water-packed tuna is usually lower in calories than oil-packed tuna, while the protein is often similar. If you add mayo, cheese, crackers, or pasta, the meal protein stays the same for the tuna itself, but the total meal calories rise quickly.
4) Avoid the most common mistakes
Don’t assume every can has the same amount of protein. A 2.5-ounce pouch, a 5-ounce can, and a 12-ounce family can are not interchangeable.
Don’t forget to check whether the label serving size is for drained tuna or tuna with liquid. And don’t round too aggressively if you’re tracking macros closely; small label differences add up over a week.
Tips
- Use the Nutrition Facts label first, not a generic food estimate.
- Drain the tuna before weighing it if your label uses drained servings.
- For macro tracking, log the whole can only after confirming the number of servings.
- Choose water-packed tuna if you want more protein with fewer calories.
- If you’re pairing tuna with training, tools like Fitnit can help you track workouts at home with your phone and keep your routine consistent.
Sources
- FoodData Central — USDA
- Nutrition and Healthy Eating — Mayo Clinic
- Exercise & Fitness — ACE Fitness
Frequently Asked Questions
How much protein is in a regular can of tuna?
Most standard 5-ounce cans contain about 25 to 30 grams of protein, depending on the brand and whether the label lists drained weight.
Is protein different in water-packed vs. oil-packed tuna?
Protein is usually similar, but oil-packed tuna has more calories and fat.
How do I count protein if the can has two servings?
Multiply the protein grams per serving by the number of servings in the can.
Does draining tuna reduce the protein?
It reduces the weight you eat, but the protein in the fish stays mostly the same; draining mainly removes liquid or oil.
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